How about (reoccuring?) events for the date when a Sci-Fi movie or a series came out?
All players will be told in advance by email or ingame notice.
If it was… say ALIEN, people are given coordinate to see “Nostromo” fly by. Stop. Eject a small transporter to a planet. Return after a couple of minutes. A few minutes later the small craft escapes the area and “Nostrome” self-destructs.
If it was Star Trek, one could have an encounter with the BORK-Cube, one of the Enterprises and or an Imperial Klingon Vessel.
Firefly
Star Wars. People could join in blowing up the Death Star. All being Player killers or having a Bounty of a certain number and above on them, may only choose Tie-Fighter at the nearby station. everyone else are free to choose Tie-Fighter or X-Wing. Just like when people are able to click on “Board my Corvette”.
Coordinates will be given and only Tie-Fighter and Death Star will be able to damage X-Wing and X-Wing vice versa.
On July 21., the date of the moonlanding, the command- and moon module of the SATURN V Rocket could fly by and orbit a moon.
April 12th, a Vostok 1 could orbit a planet to commemorate Cosmonaut Yuri Gagarin - the First human in space.
Any other?